Childhood lead exposure may adversely affect adultsâ personalities, according to a new study published by the National Academy of Sciences. The study, which sampled over 1.5 million people in Europe and the U.S., found that lead exposure in childhood may lead to lower levels of conscientiousness and agreeableness and higher levels of neuroticism, thus linking atmospheric lead in the developmental environment with less adaptive personalities in adulthood.
Even at very low levels, lead exposure has been found to cause adverse effects in childhood behavior, including poor academic achievement, compromised cognitive functioning, higher rates of problem behavior, and later life outcomes, including psychiatric dysfunction and antisocial behavior. While largely unexplored, studies on the effects of childhood lead exposure in adulthood have suggested greater levels of psychopathology and the development of difficult personality traits.
Ted Schwaba, the studyâs lead author and a postdoctoral fellow at UT Austin, stated that the apparent link between lead exposure and less adaptive personality traits is âquite impactful,â because, as the authors explain:
âWe take our personalities with us everywhere. Even a small negative effect of lead on personality traits, when you aggregate it across millions of people and all the daily decisions and behaviors that our personality influences, can have really massive effects on well-being, productivity, and longevity.â
The study sampled historical atmospheric lead data from the Environmental Protection Agency and linked this data with results of online personality questionnaires from people who grew up in the sampled areas. In general, adults raised in areas with higher atmospheric lead levels exhibited less agreeableness, conscientiousness, and more neuroticism in their 20âs and 30âs, compared with adults who did not grow up in high-concentration areas.
âNormally,â Schwaba notes, âacross the lifespan, people become more conscientious and agreeable, and less neurotic.â This, however, was not the case with individuals exposed to higher levels of atmospheric lead.
These findings add urgency to what many have already known to be a pressing environmental and racial justice issue. In the United States and elsewhere, environmental hazards such as lead are more likely to be located in communities of color, poor communities, and among populations with little economic or political power. As Schwaba notes:
âBlack children are twice as likely to have high levels of lead in their blood as white children. From an economic standpoint, from a social justice standpoint, or really any way you look at it, itâs incredibly important to limit lead exposure as much as possible.â
Achieving equity in atmospheric exposure to lead will take concerted efforts on multiple fronts, including land use, resource allocation, environmental regulation, and the provision of opportunities for participation in public processes, such as licensing and permitting facilities that emit toxic and carcinogenic chemicals in poor communities and communities of color.
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Schwaba, T., Bleidorn, W., Hopwood, C., Gbeauer. J., Rentfrow, J., Potter, J., and Gosling, S. (2021). âThe impact of childhood lead exposure on adult personality: Evidence from the United States, Europe, and a large-scale natural experiment.â Proceedings of the National Academy of Sciences, 118(29): e2020104118. (Link)
When I was lecturing in criminology about 20 years ago there was a huge debate among academics as to why the violent crime rate had risen remorselessly since the late 60s across most of the developed world, only to start dropping steeply from the mid-90s onward.
The arguments generally split across the usual left/right divide. One side saying the 60s rejection of authority and emphasis on individual rights had pushed crime up and increasing imprisonment and zero-tolerance policing was bringing it down. The other pointed to reduction in social safety nets and widening gaps between rich and poor as the cause and more data informed, evidence based criminal justice and rehabilitation programs as the cure. Both sides tried to fit patterns of illegal drug consumption (e.g. the ‘crack’ epidemic) and media portrayals of criminality into their arguments. There were also some outliers, like the authors of ‘Freakonomics’, who claimed changes in the availability of abortions among the impoverished (especially non-whites) explained it all.
Turns out they were all wrong.
It was only when people started comparing levels of environmental lead pollution to violent crime rates in the relevant regions about 15-20 years later that a clear pattern began to emerge. Turns out if you want to turn someone into a violent criminal the best way to do it is expose them to lead in their early childhood. The most effective crime reduction programs of the 20th century were the elimination of lead additives to petrol and paint.
Though there’s been a lot of follow-up studies all around the world replicating and confirming those findings, you pretty much never hear it mentioned in the mainstream media and even criminology textbooks barely touch on it.
I wonder why.
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I suffered lead poisoning from chewing on a big wad of pure lead Christmas tinsel when I was 3 or 4 yrs old (believe it or not they actually made it of lead back then, in the mid 1950’s. I can attest that lead is sweet. Sickly sweet.) The incident was all hushed up, I don’t know if I received any medical help for it and I still can’t get answers from my older half-sister who discovered that I’d fallen flat on my face and couldn’t get up.
I never completely blocked it from my memory, but the Flint, Michigan outrage of a few years ago brought it back front and center in my mind and allowed me to fit some missing pieces of myself back into place. As often happens to kids who’ve suffered lead poisoning, I became an alcoholic and drug addict at a young age but have been clean and sober for over 40 years now. In addition to the lead poisoning, I’ve had 4 concussions, two of which I developed aphasia from, the last of which (in 1994) also left me briefly comatose and caused me to develop epilepsy and a speech impediment that I still have today.
Also, I read somewhere that lead poisoning survivors sometimes feel as if their legs are dead, and that’s exactly how mine felt periodically up to about 20 years ago.
At 68, I’m still trying to make something of my life. My father was the gloomiest guy I’ve ever met, (he never got over the death of his first wife, my mother once told me.) The only times I ever saw him smile were when he told me I’d never amount to anything. Ever. It was positively obscene, but of course there were no words for that 60 years ago. He must have known something about the difficulties that lead poisoning survivors face because that was already common knowledge in the 1950’s, and he and my mother were both college educated, but nooooo, I was just a BAD KID because I couldn’t pay attention in school or tolerate frustration or say no to a drink. But oddly, six and half decades after I was poisoned, with long term sobriety and a furious exercise regimen I’ve stuck to ever since I sobered up, I feel like the fog is finally lifting from my brain. I’m doing creative work I never imagined possible. So yeah, there’s hope, even after suffering very severe childhood lead poisoning. Once it affects your motor abilities, you’re pretty close to death, and I was there.
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Lead is also responsible for inducing hyperactivity in children, which leads me to wonder why this isn’t routinely checked for prior to prescribing ritalin and other stimulants. Speed isn’t going to do you much good if you’re lead crazed, although the doctor can now believe you’re a disordered personality, to absolve himself/herself from guilt by bungling.
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